By Martin Fricker Police missed a chance to arrest Valdo Calocane just weeks before he went on the rampage, it has emerged. The paranoid schizophrenic, 32, was reported on May 5 after attacking two colleagues at a warehouse when he was already wanted for failing to attend a court hearing in 2022. Officers were still probing the attacks when Calocane killed students Barnaby Webber and Grace O’Malley-Kumar, both 19, and caretaker Ian Coates, 65, in Nottingham on June 13 last year. Leicestershire Police confirmed officers were called following two assaults at the Avarto warehouse in Kegworth. The…